Proton Deflectometry of Electric and Magnetic Fields

Highly penetrating proton beams, generated by irradiating a thin foil target with picosecond laser pulses at intensities up to 10$^{20}$ Wcm$^{-2}$ have been used to detect electric and magnetic fields in laser-produced plasmas [1]. More recently experiments to characterize the transient electric and magnetic fields using mono-energetic protons from imploding D$^{3}$He-filled capsules have been performed [2]. In the deflectometry technique a beam of protons is passed through a mesh to generate a grid of proton beamlets. This proton beam is passed through the laser-generated plasma and the grid deflection can be measured. We report on LASNEX calculations of such laser-produced plasmas, which predict electric fields of the order of 10$^{9}$V/m and 1MG magnetic fields. We will show \textsc{Lsp} calculations of proton transport through such electric and magnetic fields and compare them to the experimental data. [1] A. J. Mackinnon, \textit{et al.}, Rev. Sci. Instrum. \textbf{75}, 3531 (2004). [2] C. K. Li, \textit{et al.}, Bull. Am. Phys. Soc \textbf{50}, 266 (2005). This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48. The experimental work was performed at the LLE National User's Facility under grant number DE-SC52-04NA25436.